1. Field of the Invention
This invention relates generally to an improvement of body exercise devices utilizing dollies supported for movement along guideways so that a person standing on such dollies exercises by moving his feet in opposite directions and returning them to the original position or by simulating the leg movement peculiar to cross-country skiing.
2. Description of the Prior Art
Various types of exercise devices involving dollies and guideways have been developed in the prior art. Such devices allow the body, particularly the legs, to move in simple, natural rhythmic motion. The long, flowing movement of the legs gives exercise to the entire lower body, with particular benefit to the thighs, hips, waist, and buttocks. By using hand-held balancing poles in conjunction with the dollies, the upper body, including arms, shoulders, chest, and back, is firmed and strengthened.
Some prior art devices have been designed such that the user's entire foot, both heel and toe, is firmly restrained on the dolly. Such an arrangement does not allow the full freedom of movement of the foot desirable for such exercise. Other prior art devices incorporate a shoe hinged at the toe, such as with a cross-country ski shoe. While allowing greater freedom of movement, the latter arrangement is often complex in structure and costly. In addition, there may be inconvenience involved in fastening the straps or other attachment devices which hold the foot. In still other prior art devices, the user's foot rests by friction and the force of gravity on a dolly having a hard rubber tread, e.g. Ehrmantraut U.S. Pat. No. 3,559,986. Such an arrangement, while allowing the necessary freedom of movement of the foot, results in less control of the dolly than the earlier discussed arrangements. It may also be uncomfortable or otherwise unsuitable for use with bare feet.
Prior art exercise devices involving dollies without guideways can also be unsatisfactory, because, as the feet move in opposite directions during the exercise, the dollies can collide or, alternatively, progressively move an uncomfortable distance apart during exercise. Adding guideways to such devices is an improvement that prevents such collisions, but it may not serve to maintain the dollies at a comfortable distance apart, because the guideways themselves may move apart. The user's weight is roughly centered between the two guideways. Thus, the natural movements of a user exercising will often create a force perpendicular to the length of the guideways that tends to push the guideways apart.